1. Field of the Invention
The present invention relates to a notched wire, a notched wire element, and a filtration apparatus using a notched wire element.
2. Description of the Related Art
Conventionally, wire elements are used as filtering nets of filtration apparatus. Wedge-type wires and round-type wires are known as wires of wire elements, and wires called notch-type wires (hereinafter referred to as “notched wires”) have come to attract much attention in recent years. A notched wire is such that one surface of a band plate made of a material such as stainless steel that is superior in strength and corrosion resistance is formed with projection stripes at prescribed intervals. A wire element (hereinafter referred to as “notched wire element”) is constructed by winding a notched wire spirally around a filter cylinder, for example, in such a manner that its adjoining sections come in contact with each other in the vertical direction. A fluid to be filtered is caused to flow between the gaps formed by the recesses between the projection stripes of the notched wire element, whereby particles whose diameters are larger than the projection stripe height are removed (refer to the following documents (1)-(3)).
(1) Japanese-English/English-Japanese Dictionary of Fuel and Lubricant Technical Terms, p. 235, edited by The Marine Engineering Society in Japan, Seizando Shoten.
(2) “JIS Filters for Marine Engine Inlet Lubricant Piping System and Fuel Piping System (JIS F7103),” 1992, Japanese Industrial Standards Committee.
(3) JIS F Standards 2001, “Explanations of JIS F7103 Filters for Marine Engine Inlet Lubricant Piping System and Fuel Piping System,” pp. 2-228 to 2-234, 1994, Japan Marine Standards Association.
Incidentally, in notched wire elements, to reduce the minimum size (particle diameter) of foreign substances to be captured in a fluid, it is necessary to decrease the height of the gaps by lowering the projection stripes. However, lowering the projection stripes decreases the open area ratio of the gaps and hence increases the flow resistance. To prevent such increase in flow resistance, it is necessary to increase the total open area ratio by decreasing the thickness of the band plate that is formed with the projection stripes. However, decreasing the thickness of the band plate lowers the strength of the notched wire and hence lowers the durability. A notched wire and a notched wire element are desired that are sufficiently strong and can reduce the minimum particle diameter of foreign substances to be captured while preventing increase in flow resistance.